Marine engine



FIG. 1 is a front perspective view of a marine engine showing our new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a rear view thereof.

The broken lines in the figures show portions of the marine engine that form no part of the claimed design. 

CLAIM The ornamental design for a marine engine, as shown and described. 